Where did the Lewis and Clark expedition begin? Hint, "the gateway to the West".

How did the size of poland territory change from 1701 to 1772?

What happened right after the battle of concord ?

The rise of advertising in the 1920s. i am good with seeing how advertisements shape the roaring twenties and how it developed a new way of life through modern days. but i am not sure what the details of advertising in the 1920s were. if possible can you send me links (preferrably credential links) to sources that maybe show like the first company to start advertising through the radio, how advertising benefits (statistics graphs), etc.